Process of and apparatus for drying fabric webs



March 30 1926.

J. H. WALSH D APPARATUS FOR DRYING FABRIC WEBS PROCESS OF AN Filed April 14, 1922 4 Sheets-Sheet 1 5; 4 4M MW diijla March 30 1926.

J. H. WALSH PROCESS OF AND APPARATUS FOR DRYING FABRIC WEBS 4 Sheets-Sheet 2 m fivejvl'or o se ah ifllials'ip 4M 'zzgy.

Filed April 14, 1922 March 30 1926. 1,578,298

J. H. WALSH.

PROCESS OF AND APPARATUS FOR DRYING FABRIC- WEBS ,Filed April 14, 1922 4 Sheets-Sheet 5 7 71,067 @160 7 Joseph/ f ZI/als7v,

March 30 1926.

J. H. WALSH PROCESS OF AND APPARATUS FOR DRYING FABRIC WEBS Fil pril 14, 1922 4 sh ets-sheet 4 I u m n n n I a u.

LE e 7 7/290 7" UNITED STATES PATENT QF Ic a'osnrn H. WALSH, or BOSTON, MASSACHUSETTS, ASSIGNOR T JOHNS-alumna,

mconrom'rnn, or NEW YORK, 11. Y., A conronarron NEW YORK.

PROCESS OF AND AIPARATUS FOR DRYING FABRIC WEBB.

; Application filed April 14, 1922. Serial 11 0. 552,723.

To all whom, it may concern: I

H Be it known that I, JOSEPH H. WALSH, a citizen of the United States of America, and resident of Boston, in the county of Suffolk I and State of Massachusetts, have invented new and useful Improvements in Processes of and Apparatus ,for Drying Fabric Webs,

of which the following is a specification.-

This invention concerns the art of drying, 1 and relates more particularly to improvenients in a processof drying material in the form of. a continuous strand or web and to an'apparatus for use in carrying such proc-' ess into elfect in which the web of material 15 to be dried iscaused' to travel through a tortuous path alternately passing over and under hollow cylinders or cans which are maintained at a relatively high temperature and by contact with which the material is dried. Asia usual practice the-cylinders or cans are heated to a .high temperature by steam admitted to their interiors and this temperature is necessary to the complete expulsion of the moisture from the materia'l as the latter passes through the apparatus Damage from too great heating in such driers is frequent, and particularly not1ceable in the case of textile fabrics, such as woolens, the fibers of which may be disarranged locally by the sudden generation of steam from the moisture contained therein;

Goods so -treated are regardedin the trade as inferior to air-driedmater1als,' and thus,

even though in other respects carefully and.

skillfully fabricated, such goods are unable to compete in the open market-with those which have been air-dried. The drying of material by the above method is moreover extremely uneconomical of heat for several reasons, among which ma be noted-theifact that for the thoroughdrymg of the material in the limited time, available the temperature I of the heating drums or cansmust be kept relatively high, necessitating the employment of a" 'very considerable quantity of steam. Furthermore, the moisture expelled from the material tends to cling more or less to the surface, where it is readily reabsorbed, while at the same time such expelled moisture increases the humidity ofthe drying chamber so that the difiiculty of further evaporation is greatly increased. Another and important lossin economy results from the fact that the latent heat of the moist air of the dryingroom is {usually entirely wasted by exhausting it directly into the outer atmosphere,'-wh1le fresh air, having a relatively low temperature and consequently a great heat absorbing capacity, is drawn 1n to take its place. In many establishments,

as for example those devoted to the manufacture of paper, the total quantity of heat thus consumed in the drying room is truly enormous andv may constitute a very substantial part of the total heat consumption of the plant. Objects of the present invention are accordingly to provide an improvement in that method of, drying material in continuous web or strand form wherein the temperature of the material is raised by direct contact with a heated surface, together with apparatus suitable for carrying such process into effect, of such a'character as-to permit I of the rapid drying of the material at a tem- .perature so low as'to avoid scorching or other appreciable damage, and to efiect a substantial economy in the quantity of heat consumed in the'process. 1

' This object may well be attained by main- .taining the heating drums or cans at a much lower temperature than that commonlyemployed; and preferably substantially below the boiling point of the liquid with which 7 the material to be dried is moistened, while supplementing the drying action of the drums by jets'or blasts of, air directed againstthe material and preferably into the to remove moisture therefrom by direct absorption and at the same time serving mechanically 'tofcarry away moisture ex- 'pelled from the material on contact with the heated drums. In this manner the relative humidity or vapor pressure in the drying room-is prevented from rising to a substantial degree so thatvaporizatmn takes place at a lower temperature'than usual, thus per-e mitting the heat of the'cans or drums to be r correspondingly, diminished without. substantially increasing the duration of the l drying process; In some cases the heating of the drums, (or of the preliminary or first drums) by steammay be-'"entirel dispensed with, as the incoming air jets, isufficientlyheated, serve to raise the temperature of the web on the metallic drums to the desired point. If desired, the air jets may have a temperature substantially greater than that permissible in thedrums without occasi0n-' ing damage tothe goods, as the heat of the air jet is quickly dissipated and the movement of the fabric is such that the latter does not remain in contact with the heated jet long enough to sustain any appreciable damage.

Preferably, and as conducive to economy inoperation, the air delivered from the jets i chambers The accompanying drawings illustrate by way of example an apparatus suitable for use in attaining the above objects, and said drawings,

' Fig. 1 is a horizontal section on the line arr-b of Fig. 2,- certain' parts belng broken away;

Fig. 2 is an elevation partly in vertlcal sectionon line C"d of Fig. 1 Fig. 3 is a fragmentary horizontal section to enlarged scale through the side wall of the, housing in which the apparatus is enclosed;

Fig. 4 is a transverse vertical section on a linesuch ass-f ofiFig. 2;

Fig. "5 is a cross section, modified form ofeconomiz'er construction; and i Fig. 6 is a vertical section substantially on the line 6.6 of Figs. 1 and 4.

The drying apparatus preferably includes a housing or enclosure comprising the side walls 1, 2,'the end walls 3, 4 and the top wall 5. While in accordance with the broader aspects of the invention these walls may be formed of any desired material, and in any known manner, it is preferred to employ heat-insulating material. As illus-' trated, for example in Fig. 3, the stud memhers 5 serve to support an outer sheathing 6 of wood or other suitable material and an inner sheathing 7 of asbestos wood or the like. If desired, the space between the outer and inner she'athings may be filled with heat enclosure and spaced from one of the side walls, as for example the wall 1, is a vertical partition 10, preferably comprising a arranged parallel thereto.

illustrating I a p as by means of a pipe 26 to the intake side and serving to set off a plenum chamber 13.

Spaced from the opposite wall of the housingis a similar partition 14 carried upon angle irons 15, this partition, however, stopping short of the length of the housing-at the point 16, Fig.1. A transverse partition 17 serves to close the space between the wall '14 and the side wall'2 of the housing. Asim'ilar transversepartition 18 is arranged parallel to the partition 17 at a desired distance-from the other end wall 3, ofthe housing,- the several partitions 14, 17 and 18 de fining an economizer chamber. The partitions 1'1 and 18 are provided throughout their central portions with a plurality of.

into avertical flue 20, which extends between the partition 18 and a second partition 21 The partition 21 also serves to define a second vertical flue 22 between such partition and the end wall 3 of the housing. The last-named flue extends from the bottom to the top of the housing; while the flue 20 is closed at its lowerend by a plate 23, Fig. 4,-- lying in a plane immediately below the lowermost of the tubes 1.9. It will thus be apparent that the flue 2O communicates with the interior of the housing only by means of the tubes 19, while the flue 22, which extends substantially to the floor of the housing, communicates freely with the space surrounding the tubes 19. If desired, a series of transverse baffle plates 22 may be provided which compel the entering air to move downwardly to the bottom of'the stack of tubes before it can" movelaterally toward the flue 22. At the the space above the tubes19, and such openings may be controlled by means of damper members 25 or in other (lesired'manner.

The upper end of the flue 22 is connected of an exhaust fan 27. mounted upon a bracket 28 or other suitable support. 'The delivery end of thefan 27 is connected with a pipe 29 which communicates at the point.

vention it is preferred to extend such pipe to some point where warmed and moistened air may be found useful. If the drying apparatus herein described is employed in a textile mill for drying the finished material,

The space between the partitions and 14 constitutes a main drying chamber 32 of the housing, within which a pair of parallel vertical frames 33 and 34 are arranged.

' into and from the interiors of the hollow I a pair of nozzle slots 45, 46 r'espectively, such- These frames areof any suitable construction to support the trunnions 35, 36 ofnpper and lower series of the drying drums or cans 37, 38. The trunnions 35, 36 are preferably hollow to .permit the introduction and exhaust of steam or other heating fluid drums or cylinders in a manner well knownin the art. The drums, orcans as they are commonly known in the art, of the up :er series. are preferably disposed *vertica ly above the spaces between drums of the lower series and in such manner that theweb'39 of material, Whichfor example may be paper,

I textile fabric, or the like, which is to be dried and which'may enter the housing through an opening such as 40 inflthe wall 4, is caused totravel alternately over and under drums of the upper and lower series respectively until it emerges from the housing through the opening 41. The preferredarrangement of the drums and web, as herein disclosed, is such that the web contacts with the outer peripheral surfaces thereofthroughout' arcs of more than'a semi-circumference, the points of tangencof the webin approach: mg the. drum an in leaving the drum as shown being substantially 90, apart, such points being indicated for example, at 42, 43 respectively, and it will be noted that while one surface of the web. contacts with surface of the drums of the lower series, so

that extensive contact with-thehot surfaces and efficient drying action is secured. -Wi'thin the spaces beneath the drums 37 and in parallel with the axesof the respective drums of the upper series are arranged nozzle tubes 44. These nozzle tubes are preferably" tapered from one end to .the other, the larger ends thereof being secured within openings in th e partition 10, such larger ends being open while the 'smallem ends thereof are closed. These tubes are each'furnished with slots being preferably slightly tapered to- -ward the small end of the'tubes and being so disposed angularly of the tube as to direct the air discharged therefrom; into the inc'ludediangles 47, 48 respectively between the drum surface and the approaching and leav heating pipes or coils 50;51, respectively ing portions of the web. Similar nozzle tubes 49 may be disposed in the spacejimmediately above the drums 38, as indicated in Fig. 2'. Within the plenum chamber 13.,

there are arranged: one or more stackf's "of such coils being supplied with steam or, any heating medium from other suitable sources.

The operation of the device is substantially as follows, it being understood that the web 39 enters through an opening 40,

passes over and under the'respective rolls or drums, and out through an opening 41,

point of the liquid with which the material to be dried is moistened. The fan 27 being set in motion draws air upwardly from the. flue 22 and discharges it through the pipe 29 into the plenum chamber '13. Such air in passing over the coils 50,, 51 is raised in temperature to the desired degree andv then passes'out through the tubes 44 and is dis-f charged through the slots 45, 46 into the The drums may be spaces beneath the drums 37 and above the drums 38, if desired. It will be evident from the position of the discharging nozzles, that the warmed air contacts. directly with the web at those points where such web approaches and leavesthe drums, while" at the sanie time thenwarmed air is brought into contact with the surfaces 9f the drums them selves. The surface ofthe drum is; thus freed'from any moisture which'it may carryin moving away from the web, as at the point 43, while at thesame-time the surface of the web-to which acertain amount of vapor may cling, due to the action of theheated drum immediately preceding; is

swept free of. such vapor by action of the 'air' current issuingfrom the nozzle openin'g.' The drying action of the drums is .thus facilitated by the employment of the warmed air blast at the-point indicated, and

furthermore, such blast may be heated toa high temperature, if desired, so that the air of such blast possesses a relatively high capacity for the absorption'of moisture en abling-it to abstract moisture from the web very rapidly; By reason of the movement of the web and the rapid movement off the air from the jet, there is little if anydanger of damage to the fabric by overheating-the same such as frequently occurs when it "is attempted to employ drums heated to a similar temperature. The warm'air escapingfrom the nozzles and after contacting with the surface of the web and drumpasses do'wn wardly' between the lower rolls or endwise through'th'e frame members 33, 34 and into the main body of the drying chamber 32.

drying chamber, this warm and moistureladen air, which passes out from between ;As the fan continues to force air 'into'the,

' dimensions thereof and 'thelmaterials e .155 larly where corrosive fumes i 6 in place of the tubes previously permitted to enterthe same. I In passing over the pipes 19 such fresh air is warmed to a 'very'considerable degree, the outgoing air passing throughthe pipes 19 parting vith a portion of its heat, so that a very substantial economy of heat is secured. The

operation thus continues as the web is drawn through the apparatus, the additional heat necessary for bringing the air. jets to the desired temperature being furnished, by the coils 50 and 51, as abovedescribed.- 1n 5 some cases it may be found that such C01lS are unnecessary providing the cylinders 37 38 are maintained at' a sufliciently high temperature. In certain instances, however, it may be'founddesirable to dispense with the heati sion of of, and to depend upon the heat of the air jets for imparting t p to such cylinders. In such case the co1ls 50, 51 are obviously necessary, and the temperature of the air, prior to its discharge relatively high degree, itv being noted that thecylinders tend to conduct away the =heat of v'thejet very rapidly and to impart 1 heat to the web which lies in contact there- 4 with throughout a very substantial portion of the .length thereof, while at the same time the' flow of air from the jets serves to A earryaway moisture directly from the ad a-- cent portionof the web." AItho-ugha pre-- 4'5 ferred form of the invention has been :de-

scribed hereinabove, it is to be understood that such invention in its broader aspects- ;m ight be embodied in difi'erent forms of'ap paratus and that modifications in the shapes and. arrangements of parts, as well as the m- )loyed may well be made without departing ctrom the spirit of the invention.

Under some circumstances and particuarise from. the material in drying it may bed-esirable to construct the economizer devicein a manner somewhat different from that 0 above described. As shown in Fig. 5 for example, referred to the economiz'er device, comprises a series of thin vertical partitions 52 arranged withinthe economizer chamber and extending longitudinally thereof. Such partitions are pref! crably of corrugated material and if desired ng of the cylinders, by,the' admis-' heated fluid to the interiors there-- he desired temperaturefrom the jets may be raised thereby toga may be of sheet asbestos, enameled metal or some other substance which is resistant to the corrosive effects of acids or other chemical substances which maybecarried by the vapor evolved'in the drying process. These partitions are connected in pairs by upper and lower members 53, 53 respectively, whereby longitudinal} passages 54 are formed, such passages being open at their ends where the'partitions 52 are secured to the edges of; slots formed in the partitions 17, 18 previously described. ---The passages5e alternatewith vertical fiues .55'closed at their opposite ends by the partitions 17, 18 respectively but open at the'top and bottom. The passages 54 correspond to the tubes 19 of the previously described economizer device while the fines 55 "correspond to the spaces between the'tubes 'of'the aforesaid device. The flues 55 communicate at their lower ends with the space leading to the fine 22 whilc at their upper ends they communicate with the "space into which the air :inlet duct 2a'opens. The ends ofthe pas'sages 54.communicate respectively withthe flue. 20 and with the dry- 1 ing chamber. ,By the employment of the corl .-rugated partitions a very large conductive surface is provided for the transfer of heat so that it is possible to employ a material having a relatively low conductivity and at 95 the same time permitting the manufacture of such partitions fromcorrugated sheet material by a stamping or similar process.

What I claim is: i v I 1-. That processofldrying webs of tex 100 -ti1 e fabric. which comprises passing such a web through a-heat'insulated housing and such during its passage alternately subjecting the web tothe drying action of a blast. of

heated gaseous fluid of substantially uni form intensitytransversely of the web and -to that of a, heated solid with which the web is caused directly to contact.

2. That process of drying material in the form of a continuous web which comprises passingsuch web alternately over an dunder I rotary drums arranged in series in a heat insulated housing, drawing air from the Ispace adjacent to. said drums heating fresh air, and directing a blast of-such heated air into the included angle between the surface of 1:me of said drums and the -approaching we I 3. A drying apparatuscomprisinga housf ing having a plurality of spaced, "heatconducting surfacestherein constructed and arranged for successive engagement by the .material to be" dried, .means for-delivering heated air 'at points intermediate certain, at

least, of said surfaces to absorb moisture from the material, means causing moisture" laden air to flow. from 'thehousing, and heat exchange means for conserving a portion I ofthe heat contained in such moisture laden air for further use. I

4.- A drying apparatus comprising a housing having heat insulating wallsfa plurality of" drying cylinders in said housing, air

delivery nozzles interposed I betweeri.:-certain of said cylinders, means for withdrawing air from said housing, and means whereby heat from said outgoing air is iinpartedto air on its way to the nozzles.

5. Drying apparatus comprising a series of heated drying drums, means for delivering blasts of air at points adjacent to 6. A drying apparatus comprising a hous ing for the reception .of surface contact drying means, a passage at oneside of said housing; nozzles .communicating with said,

passage and disposed adjacent to. said surface drying means, aneconomizer device,

and means for inducing a'current of fresh a1r tosflow 1n one directiomthrough said economizer device and into said passage for delivery from the nozzles while causing air in the op from adjacent to said drying means to flow posite direction through the economizer device.

7. 'A drying apparatus comprising a hous ing, a vertical partition at one side of said housing defining a plenum chamber, a sei ries of nozzles within sa-idhous'ing and communicating withthe plenum "chamber, an economizer device at the opposite side of the housing, said economizer device comprising a casing having a plurality of thin metallic walls defining passa es extending-I longitudinally thereof, a flue or the ingress of fresh air into thespaee between said passages, and an exhaust fan for drawing air from said space and delivering-it to the plenum chamber whereby warm air from the housing is displaced-and forced to flow through the economizer device.

8. A drying apparatus comprising a housing, having heat insulated walls, continuous ly moving heated surfaces within said housing ,for drying material by contact there-"- with, means for. withdrawing air from the housing and for inducing the entry of fresh air into the housing, such fresh a r passing in heat transferring relationship to such withdrawn air, and a conduit leading from.

the housing for -conducting away the withdrawn and. partly cooled air.

" ing having .a .plenumchamber, afldryin said drums and. communicatingwith saidchamber and a regenerator chambenheate drying drums withinfthe. drying chamber,

air. delivering nozzles inters rsed among plenum chamber, heatingv coils within said.

latter chamber, and means for inducing" a. flowof fresh airthidughJ-the regenerator chamber, the plenum chamber and the delivery nozzles while causing the discharge of warm and moistair from: the drying chamber and through the regenerator chamber. -10. A drying apparatus comprising a housing having walls of heat insulating material, drying drums therein, a regenerator device having a plurality of substantially parallel flow passages and means for inducing a flow of fresh air through certain of said passg'es and into the housing at a point adjacent to said drums, said means thereby serving to force air from within the housing to pass outwardly through passages of the regenerator intervening between sald certainpassages.

11. A drying apparatus comprising a housing having a 1 drying drum therein, means for guiding a moving web of material into Contact therewith, and a nozzle tube having elongated air delivery slots positioned. adjacent to that portion of the .drum at which the material passes out of contacttherewith, and substantially parallel to the axis of the drum, said tube being constructed and arranged. to deliver blasts of" warm air against the material'on its .passage -'to and its passage away from said drum.

12..-An apparatus of the-class described comprising a housing of heat insulating material, means for supportingfabric there-' in, means fordirecting a current of heated air into. contact. with the l fabric so supported, and, an economizer device comprising a series of parallel passages separated by thin corrugated partitions, and through alternate passages of which a-1r is caused'to travel in opposite directions in leaving said housing.

i 13. In. combination with a drying apparatus, an elongate compartment having a pluentering and rality of substantiallyparallel, vertical partitionsof sheet material defining a'series. of

narrow passages between them, an inlet for fresh air communicating with alternate passages of said series, a discharge du-ct communicating-with the opposite ends of said passages, and inlet and outlet passages communicating with {the opposite ends respectively of the other set of passages.

14. In. combination. a drying ap aratus,

an-economizer, device comprising s eet's of corrugated material disposed. in substantially parallel relation, said sheetsv being 'connecte p v edges whereby to' provide passages opening I 9. A drying apparatus comprising. a housj in pairs at their longitudinal alternately at the ends of the-device and at partmenttherein having walls of heat. insulating material, an economizer device in said compartment comprising a ,series' of thincorrugated partitions defining: a plurality of substantially parallel,"na'rrow pas sages, an air inlet communicating with alternate passages .of said series at; one end thereof, 'a chamber having heating means therein andtco mmunicating with the opposite ends ofsaidpassages', a fan for induc ing 'the flowof-air through said passages and heating chambeninto said housing, and,

a passage-leading from said housing to the other passages of said series, theparts be-' -ing so constructed and arranged that all i flowing intosaid housing moves through the passages of the economizer in .a direction substantially transverse to the flow of outgoing air in theadjacent passages.

Signed by me at Boston, Massachusetfsylo this twenty-eighth day of January, 1922.

f JOSEPH H. WALSH 

